Once in the female reproductive tract, spermatozoa undergo several modifications to acquire their complete fertilizing ability. Interactions between the oviductal fluid (OF) and gametes contribute to a successful fertilization. Recently, oviductal extracellular vesicles have been identified as an important part of the OF but their interactions with gametes are not fully understood. In the present study, we aim at determining the patterns of interactions between porcine oviductal extracellular vesicles (poEVs) and gametes (spermatozoa and oocytes). Moreover, we evaluate the effect of poEVs on sperm survival and motility to better understand the mechanisms by which poEVs modulate the processes leading to fertilization. Evaluation of poEVs uptake by spermatozoa showed that poEVs bind to spermatozoa in a time and dose dependent manner. Co-incubation of spermatozoa with poEVs (0.2 μg/μL) increased fresh and frozen sperm survival after 6 and 17 h, respectively. By contrast, poEVs supplementation reduced the total and progressive sperm motility after 2 h. Additionally, we demonstrated that poEVs interacted with the cumulus cells, zona pellucida (ZP) and oocyte, being able to cross the ZP. Besides, we showed that poEVs delivered their cargo into the oocyte, by the transfer of OVGP1 protein. In conclusion, our results demonstrated that poEVs are able to interact with both gametes. Besides, the findings from the present study showed that poEVs may participate in maintaining sperm viability and reducing motility, functions associated with the oviduct sperm reservoir. Although further investigations are needed, our results indicate that poEVs can be a potential tool to improve sperm life span during sperm handling and enhance IVF outcomes.

中文翻译：

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猪输卵管细胞外囊泡与配子相互作用并调节精子活力和存活

一旦进入女性生殖道，精子会经历多次改造以获得完整的受精能力。输卵管液 (OF) 和配子之间的相互作用有助于成功受精。最近，输卵管细胞外囊泡已被确定为 OF 的重要组成部分，但它们与配子的相互作用尚不完全清楚。在本研究中，我们旨在确定猪输卵管细胞外囊泡 (poEV) 和配子（精子和卵母细胞）之间的相互作用模式。此外，我们评估了 poEVs 对精子存活和运动的影响，以更好地了解 poEVs 调节导致受精过程的机制。对精子摄取 poEV 的评估表明，poEV 以时间和剂量依赖性方式与精子结合。精子与 poEV (0.2 μg/μL) 的共孵育分别增加了 6 小时和 17 小时后新鲜和冷冻精子的存活率。相比之下，补充 poEVs 会降低 2 小时后的总和渐进性精子活力。此外，我们证明了 poEV 与卵丘细胞、透明带 (ZP) 和卵母细胞相互作用，能够穿过 ZP。此外，我们还发现 poEV 通过 OVGP1 蛋白的转移将其货物输送到卵母细胞中。总之，我们的结果表明 poEV 能够与两个配子相互作用。此外，本研究的结果表明，poEVs 可能参与维持精子活力和降低运动能力，这些功能与输卵管精子库相关。虽然还需要进一步调查，